A titration approach to identify the capacity for starch digeston in milk-fed calves

M.S. Gilbert, J.J.G.C. van den Borne, H. Berends, A.J. Pantophlet, H.A. Schols, W.J.J. Gerrits

Research output: Contribution to journalArticleAcademicpeer-review

8 Citations (Scopus)

Abstract

Calf milk replacers (MR) commonly contain 40% to 50% lactose. For economic reasons, starch is of interest as a lactose replacer. Compared with lactose, starch digestion is generally low in calves. It is, however, unknown which enzyme limits the rate of starch digestion. The objectives were to determine which enzyme limits starch digestion and to assess the maximum capacity for starch digestion in milk-fed calves. A within-animal titration study was performed, where lactose was exchanged stepwise for one of four starch products (SP). The four corn-based SP differed in size and branching, therefore requiring different ratios of starch-degrading enzymes for their complete hydrolysis to glucose: gelatinised starch (a-amylase and (iso)maltase); maltodextrin ((iso)maltase and a-amylase); maltodextrin with a-1,6-branching (isomaltase, maltase and a-amylase) and maltose (maltase). When exceeding the animal’s capacity to enzymatically hydrolyse starch, fermentation occurs, leading to a reduced faecal dry matter (DM) content and pH. Forty calves (13 weeks of age) were assigned to either a lactose control diet or one of four titration strategies (n=8 per treatment), each testing the stepwise exchange of lactose for one SP. Dietary inclusion of each SP was increased weekly by 3% at the expense of lactose and faecal samples were collected from the rectum weekly to determine DM content and pH. The increase in SP inclusion was stopped when faecal DM content dropped below 10.6% (i.e. 75% of the average initial faecal DM content) for 3 consecutive weeks. For control calves, faecal DM content and pH did not change over time. For 87% of the SP-fed calves, faecal DM and pH decreased already at low inclusion levels, and linear regression provided a better fit of the data (faecal DM content or pH v. time) than non-linear regression. For all SP treatments, faecal DM content and pH decreased in time (P
Original languageEnglish
Pages (from-to)249-257
JournalAnimal
Volume9
Issue number2
DOIs
Publication statusPublished - 2015

Keywords

  • small-intestinal disappearance
  • abomasal glucose
  • maize starch
  • amylase
  • steers
  • oligosaccharide
  • digestibility
  • secretion
  • replacers
  • infusion

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